Paper machinery



8- 7, 1951 B. J. KOZIOL 2,563,249

PAPER MACHINERY Med Oct. 28, 1948 2 Sheets-=Sheet l INVE-EJ 5Y7)? ATTORNEYS Aug. 7, 1951 B. J. KOZIOL 2,563,249

PAPER MACHINERY Filed Oct. 28, 1948 I 2 Sheets-Sheet 2 INVENTOR ATTORNEYS Patented Aug. 7, 1951 PAPER MACHINERY Bernard J. Koliol, Franklin, Ohio, assignor to The Black-Clawson Company, Hamilton, Ohio,

a corporation of Ohio Application October 28, 1948, Serial No. 52,049

14 Claims. 1

This invention relates to screening apparatus for use in the preparation of paper making stock or the like.

One of the principal objects of the invention is to provide a vibrating screen for the treatment of liquid suspensions which is of simple and compact construction, which has high operating capacity, and which is quiet in use and does not transmit objectionable vibrations to the supporting or surrounding structure.

Another object is to provide a vibrating screen of such construction that the moving parts are substantially free of dead centers where reversal of motion occurs and points subject to fatigue in operation, and thus to provide for reduced weight and bulk in the apparatus and also in its supporting structure without loss in capacity.

An additional object is to provide a vibrating screen wherein the amplitude and frequency of oscillation of the vibrating member may be quickly and easily independently varied in accordance with desired screening conditions.

Still another object is to provide a vibrating screen wherein the perforate screen member is subject to such low stresses in operation that it may be constructed of relatively thin and light sheet stock having fine perforations therein for fine screening action.

It is also an object of the invention to provide a vibrating screen wherein the perforate screen member is caused to move in an orbital path under such conditions that the stock being screened is subjected to combined centrifugal and pumping action effective both to agitate the unscreened stock and also to cause the reject material to traverse a relatively long path therein without compacting and thus to promote complete separation and discharge of the reject from the usable material.

A further object is to provide a vibrating screen wherein all parts of the apparatus which come in contact with the stock are so constructed and arranged as to produce efiectlvely a self-cleaning action minimizing maintenance requirements in use.

Among additional objects is the provision of a vibrating screen having a simple and direct driving connection to the vibrating member, free of packing boxes and like joints subject to leakage or wear in use and thus requiring minimum lubrication and maintenance.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings- Fig. 1 is a top plan view showing screening apparatus in accordance with the invention, with portions broken away to illustrate details of internal construction and arrangement;

Fig. 2 is a vertical section on the line 2-2 of Fi 1;

Fig. 3 is an exploded perspective view of the screening apparatus of Figs. 1 and 2;

Fig. 4 is an enlarged detail view partly in side elevation and partly in vertical section of one of the resilient supports for the vibrating screen member;

Fig. 5 is an enlarged fragmentary view illustrating the operation of the screening apparatus; and

Fig. 6 is a fragmentary view in vertical section showing a modified construction of drive for the screening apparatus.

Referring to the drawings, which illustrate preferred embodiments of the invention, the main casing In of the apparatus includes an inner wall portion ll of frusto-conical configuration forming a generally frusto-conical chamber I2 having its lower end open to provide an outlet l3. Thecasing I0 is constructed to provide a passage l4 leading from the outlet l3 to an extension portion [5 of the casing adaptedat l6 for connection to a suitable conduit for receiving the screened stock. A partition wall I! within the casing portion I5 is equipped with a vertically adjustable dam or flow gate l8 which provides for maintaining a desired level of liquid within chamber [2.

The casing l0 also includes a peripheral discharge trough 20 which surrounds the upper rim of chamber 12 and slopes downwardly, as indicated at 2|, to a discharge outlet 22 at the opposite side of the casing from the extension portion IS, the outlet 22 being adapted for connection to a suitable conduit for receiving reject material from the apparatus. A shower pipe 25 is mounted around the outer rim of trough 20 in position to spray water into chamber l2, and also into the trough 20 to provide liquid for washing out reject material from the trough to the outlet 22. The shower pipe 25 may be secured to the casing by brackets 26 and is shown as provided with a connection 21 for attachment to a suitable supply source of water.

A generally conical screen member 30 is mounted with its lower portion extending within chamber l2 in spaced relation with wall H to leave an annular portion of chamber 12 therebetween. The screen 30 may be constructed of suitably formed sheet stock or a plurality of sector-shaped screen plates, and its sloping side wall is drilled or slotted to provide perforations 3| (Fig. 5) of the desired size in accordance with the nature of the stock to be screened and the desired degrees of fineness in screening. The screen member 30 includes an imperforate bottom portion 32, and its perforate side wall flares outwardly at its upper end into a flat imperforate rim portion 33. This rim 33 extends outwardly into an overhanging relation with the discharge trough 20, and the portion 34 of the screen member intermediate rim 33 and the perforate side wall is curved or inclined at a less steep angle than the perforate portion to facilitate upward and outward travel of reject material.

The screen member 30 is supported bya plurality of supporting devices 35 for generally trans lational movement with respect to casing III, with this movement limited to a substantially horizontal plane, and Fig. 4 illustrates a form of supporting device 35 found suitable for this purpose. It includes a base member 40 of inverted cup shape which may be mounted on the casing as by being bolted to supporting brackets 4|. Two resilient rubber members 42 are mounted respectively above and below base 40 and are formed with radially arranged corrugations 43 on their surfaces adjacent member 40. A flanged sleeve 44 and upper collar 45 secure the rubber members in position, base member 40 being provided with a center aperture 46 with a larger diameter than sleeve 44 to allow limited movement of the sleeve as the corrugations 43 are flexed. A bolt 41 extends upward through sleeve 44 to provide for attachment to the rim portion 33 of screen member 30.

It will be seen that these supporting devices 35 normally position screen member 30 in coaxial relation with the casing wall II and chamber II but will permit limited movement of the screen member in a substantially horizontal plane as the corrugations 43 of the resilient members 42 are deflected, movement of the screen member about an orbit having a maximum radius of the order of Y. inch having been found satisfactory. A plurality of vanes 53 are welded or otherwise secured to the inner surface of wall H and extend radially inwardly therefrom to divide the annular space between wall II and screen member 30 into a corresponding plurality of generally sector-shaped compartments 5|. six of these vanes and compartments being shown. It will also be noted that the dimensions of vanes 50 are predetermined to provide adequate clearance between the inner edges of the vanes and the screen member 30 for the desired movement of the screen member.

A direct drive is provided for causing orbital movement of screen member 30 without the transmission of objectionable vibrations to casin Ill and its surrounding or supporting structure. Three arms 54 are secured to the rim portion 33 of the screen member by means of bolts 41 and extend inwardly to a central hub 55. An electric motor 56 is mounted on hub 55 with its drive shaft 51 coaxial with the vertical axis of the screen member, and an eccentric weight 58 is secured to shaft 51 for rotation therewith. Thus when the motor 50 is operated, the rotation of weight 53 will cause screen member 30 to move in an orbital path within a substantially horiaontal plane as limited by the supporting devices 35. A similar eflect may be obtained without weight I! by drilling oil-center holes at one side of the armature of motor I. to provide an out-of-balance condition.

An inlet cone provides for desired distribution and direction of flow of the incoming stock delivered to the interior of screen member 30. This cone is shown as of the same degree of taper as the screen member and wall II, and it is mounted in telescoping spaced relation with the screen member to leave an annular space 3| therebetween. The cone 6. is mounted in position by a plurality of arms 82, which extend upwardly and outwardly therefrom for attachment to the main casing as by being bolted to brackets 63. Incoming stock may be supplied to cone II in any desired manner and preferably in initially generally tangential flow, as by means of the tangentially arranged pipe 64 shown in Fig. l, to impart initial spiral motion to the stock, which thus swirls downwardly in cone 60 and then flows upwardly with a similar spiraling motion into the space 6 i In operation. the motor Bl is started to cause the desired orbital movement of the screen member 30, and stock for screening is supplied at a desired rate to the inlet cone 80, the dam II in extension casing is being adjusted to the proper height to maintain the level of liquid in chamber l2 above the lower end of cone 60 to assure the desired upward flow of unscree'ned stock into annular space 6|. It will be seen that the resultin motion of screen member 30 will subject the stock therein to centrifugal force tending to urge the liquid and fine material through perforations 3| into compartments II and tending to throw reject material too large to pass through the perforations out against the inner surface of the screen member. This motion also causes circulatory movement of the stock within space 6 I. At the same time, the relative movement of screen member 30 and wall II will subject the stock to a pumping action tending to urge reject material in space GI upwardly toward rim l3 and the discharge trough ill, as is illustrated diagrammatically in Fig. 5.

Referring to Fig. 5, which shows an enlarged and exaggerated fragment of screen member 30, a single particle too large to pass through perforations 3| is represented at 85. This particle is continuously urged upwardly and outwardly in a generally spiral path by a combination of centrifugal force and the circulatory and upward motion of the stock within space ii. In addition, this upward and outward movement is aided by the pumping action produced by cooperation of screen member 30 with the compartments 5! formed by vanes II.

Thus as the fragment of the screen member shown in Fig. 5 moves toward the right on onehalf of a given oscillatory cycle, represented by the arrows 66, it will move away from the adjacent portion of wall II and thus create suction in the adjacent compartment 5| through perforations 3|. This force is represented by the broken arrows 61 in Fig. 5 and supplements the other forces urging particle 65 outwardly, as indicated by the broken lines 63 in Fig. 5. On the next half-cycle, however, the screen member will move toward the adjacent portion of wall II, to the left in Fig. 5, and since the vanes 50 substantially prevent circulation of stock in the chamber ii. the stock in the adjacent compartment ii is subjected to compression causing a reversal of flow through the perforations 3|, as indicated by the solid arrows 83. This in turn tends to urge particles I upwardly and away from the surface of the screen member, so that on the following half-cycle, particles 65 will be drawn outwardly at a higher level than before, and this action is repeated successively at every position around the screen member and in each compartment 5| for all the reject particles.

It will thus be seen that this combined centrifugal and pumpin action and the circulatory movement of the stock in cone 60 and in annular space 6| all cooperate to urge particles too large to pass through perforations 3| to follow a generally spiral path upwardly along the inner surface of screen member 30 to the top of the liquid level in the casing. This elongated travel and the continuous agitation caused by the repeated reversal of flow through perforations 3| promotes effective separation of reject material from the usable stock of sufficient fineness to pass through the perforations, the latter being transmitted to the compartments 5| and thence through outlet l3 and passage M to the discharge outlet 16. The reject particles in turn are forced to the top of the liquid in space 6|, and as they accumulate, they are forced on upwardly and outwardly to the rim portion 33 until they fall into discharge trough 20. The shower from shower pipe 25 aids both in washing back usable fiber clinging to the reject material and also in washing away the reject after it reaches trough 20.

This screening apparatus is thus capable of operating continuously at high capacity, with the screened stock and reject continually discharging at separate locations. It will also be noted that since the reject is spread over an increasing area of the conical screen member as it moves upwardly and outwardly, it does not tend to compact and retard discharge, thus contributing to the desired high operating capacity and also promoting complete separation from the usable fiber. Furthermore, the frusto-conical configuration of the screen member and its associated cone B and wall I I provide effective self-cleaning action, free from pockets or the like within the apparatus capable of interfering with complete drainage.

The total movement of the vibrating member is relatively small and does not include dead centers or like points at which reversal of stress occurs, and it is thus unnecessary to provide a heavy supporting casing or base, adequate absorption of vibration being obtained in the resilient members of the supporting devices 35. This in turn makes possible the successful "cohstruction of the apparatus from comparatively lightweight materials at correspondingly reduced cost. Furthermore, since the perforate screen member itself is substantially free of fatigue points in operation, it can be constructed of lighter and thinner stock than heretofore found practical, and this in turn makes possible the use of finer perforations than previously available, for example, drilled holes as small as .060

inch in diameter and slots as small as .006 inch in width.

It will also be seen that the invention provides for great simplicity in the driving connection to :the vibrating screen member, the drive being applied directly to the vibrating member and thus requiring minimum lubrication. Furthermore, with the drive effected by an eccentric weight on the shaft of a motor carried by the vibrating screen member itself, the only reaction force to be absorbed by the remainder of the apparatus is the vibration transmitted through the resilient supporting units 35. This drive arrangement also minimizes friction losses and bearings and like locations requiring lubrication, and since there is no drive connection extending through any of the spaces or chambers which receive stock, there are no packing boxes or other like joints between relatively moving members which might give rise to leakage in operation.

This drive arrangement has the further advantage of facilitating simple and quick variation of the amplitude of oscillation, either independently of or concurrently with the oscillatory frequency in accordance with desired operating conditions. Thus both the amplitude and frequency may be varied by changing the speed of motor 50, examples of suitable speeds ranging from 800 to 3600 R. P. M. and the amplitude being decreased as the frequency is increased and vice versa. The amplitude can also be varied without altering the frequency, by changing the eccentric weight 58 to one of greater or less out-of-balance condition to provide a corresponding increase or decrease in amplitude for the same frequency. It will also be noted that if other conditions remain constant, the amplitude is affected by a change in the consistency of the stock being screened, the amplitude being decreased in the event of an increase in the consistency and the resulting resistance to movement of the screen member 30.

Fig. 6 shows a drive arrangement similar to that already described but in which a flexible shaft is employed for transmitting the drive to the perforate screen member from a motor or other drive source. The arms 15 in Fig. 6 correspond to the arms 54 in Figs. 1 to 3 and are secured to the perforate screen member. These arms'are bolted to a hub unit comprising a bottom plate 16 and an upper cap 11. A bolt 18 is set in plate 16 and forms a pivot for the eccentric weight 80, which is mounted on bolt 18 by means of suitable bearings 8|. Weight is shown as a disk having a plurality of circumferentially arranged bores 02, some of which are filled with lead 83 or other suitable heavy material, this arrangement facilitating the provision of multiple weights 80 of the same size but different degrees of out-of-balance condition.

A flexible shaft coupling 85 is force fitted or otherwise secured to weight 80, and it includes a central bore 86 adapted to receive the connecting prong 81 at the end of a flexible shaft 88. A set screw 90 in coupling 85 secures prong 81 in bore 86, and hub cap 11 is provided with a side hole 9| for ready access to set screw 90. A swivel collar 92 on shaft 88 is shown as threaded into the upper end of hub cap 11 to complete the coupling.

This drive arrangement as shown in Fig. 6 will produce the same operating characteristics for the screening apparatus as already described in connection with Figs. 1 to 5, and it offers advantages of quick and easy change of weight 80 as desired to vary the amplitude of oscillation of the screen member. In addition, the flexible shaft 88 can readily be driven by a stationary motor provided with variable speed means to facilitate variations of the frequency of oscillation of the screen member.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus,

aseauo 7 and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means positioning said screen member with the lower end thereof within said chamber in spaced relation with the side walls of said chamber to define therewith an annular space for receiving screened stock through said screen member, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane, means for substantially preventing circulation of said screened stock in said annular space, and means for effecting orbital movement of said screen member in said plane with respect to said casing to cause alternate compression and suction within said annular space and resulting alternate reversal of flow of the screened stock through the perforations in said screen member.

2. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member with the lower end thereof within said chamber in spaced relation with the side walls of said chamber to define therewith an annular space for receiving screened stock through said screen member, means for substantially preventing circulation of said screened stock in said annular space, means for efiecting orbital movement of said screen member with respect to said casing, and means cooperating with said supporting means to limit said movement of said screen member to a substantially horizontal plane to cause alternate compression and suction within said annular space and resulting alternate reversal of flow of the screened stock through the perforations in said screen member.

3. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member positioned with the lower end thereof within said chamber in spaced relation with the side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, said screen member being adapted to receive stock for screening in the interior thereof, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane, a plurality of angularly spaced partition members arranged within said annular space to form a plurality of compartments therein adapted to be filled with the screened stock, and means for effecting orbital movement of said screen member in said plane to cause alternate compression and suction within said compartments and resulting alternate reversal of flow of the screened stock through the perforations in said screen member.

4. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member for movementwlthrespecttosaidcasinglimitedtoa 8 substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with the side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, a discharge trough positioned to receive material discharged over the upper rim of said screen member, and means for effecting orbital movement of said screen member in said plane to cause particles too large to pass through the perforations in said screen member to travel upwardly along the inner surface of said screen member and to be discharged into said trough.

5. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, means for establishing a predetermined maximum level of liquid within said chamber, a generally conical perforate screen member positioned to receive stock for screening with the upper rim thereof extending above the liquid level in said chamber and with the lower part thereof extending into said chamber in spaced relation with the side walls of said chamber to form therewith an annular space for receiving screened stock through said screen member, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane, means for substantially preventing circulation of said screened stock within said annular space, a discharge trough positioned to receive material discharged over the upper rim of said screen member, and means for effecting orbital move ment of said screen member in said plane to subject the stock therein to combined pumping and centrifugal action causing particles too large to pass through the perforations in said screen member to travel upwardly along the inner surface of said screen member and to be discharged into said trough.

6. Screening apparatus of the character described comprising a main casing forming a frusto-conical chamber having an outlet at the lower end thereof, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means on said casing supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with the inner surface of said chamber to form therewith an annular space for receiving screened stock through said screen member, a plurality of angularly spaced partition members secured to said casing and extending inwardly of said annular space to form a plurality of compartments therein adapted to be filled with the screened stock, and means for effecting orbital movement of said screen member in said plane to cause alternate compression and suction within said compartments and resulting alternate reversal of flow through the perforations in said screen member.

'7. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, means for establishing a predetermined maximum level of liquid within said chamber, a hollow perforate screen member adapted to receive stock for screenin in the interior thereof, means supporting said screen member on said casing for movement with respect thereto with the upper rim of said screen member extending above said liquid level and with the lower part thereof extending into said chamber to form with the inner surface of said chamber an annular space for receiving screened stock through said screen member, means for limiting said movement of said screen member to a substantially horizontal plane, an eccentric weight supported on said screen member for rotation about the vertical axis thereof with respect to said screen member, and drive means for rotating said weight to effect orbital movement of said screen member in said horizontal plane with respect to said casing.

8. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a hollow perforate screen member adapted to receive stock for screenin in the interior thereof, means supporting said screen member on said casing for movement thereof with respect to said casing limited to a substantially horizontal plane, the lower part of said screen member extending into said chamber in spaced relation with the side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, a plurality of arms secured to said screen member and extending inwardly thereof to form a centrally disposed hub, an eccentric weight mounted in said hub for rotation about the vertical axis of said screen member with respect to said screen member, and drive means for rotating said weight to effect orbital movement of said screen member with respect to said casing.

9. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof. means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with the side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, a discharge trough positioned to receive material discharged over the upper rim of said screen member, an open-ended cone carried by said casing in telescoping spaced relation with said screen member to form therewith a second annular space, said cone being adapted to receive stock in the upper part thereof for transmission through the lower end thereof to said screen member for screening, means for maintaining the level of liquid within said chamber above the lower end of said cone to establish an upward fiow of stock from said cone into said second annular space, and means for effectin relative orbital movement of said screen member in said plane to cause particles too large to pass through the perforations in said screen member to travel upwardly within said second annular space and to be discharged into said trough.

10. Screening apparatus of the character described comprising a main casing forming a chamber having an outlet, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with the side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, an open-ended cone carried by said casing in telescoping spaced relation with said screen member to form therewith a second annular space, said cone being of sufficient dimensions to receive stock for screening adjacent the upper end and tangentially thereof and to deliver said stock to said screen member through the lower end thereof in a generally spiral flow, means for substantially preventing circulation of the stock within said first named'annular space, and means for effecting movement of said screen in said horizontal plane to subject the stock therein to combined pumping and centrifugal action causing particles too large-to pass through the perforations in said screen member to travel upwardly within said second annular space.

11'. Screening apparatus of the character described comprising a main casing forming a generally conical chamber having an' outlet at the lower end thereof, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, an openended cone carried by said casing in telescoping spaced relation with said screen member to form therewith a second annular space, said supporting means for said screen member including resilient means normally positioning said screen member in concentric relation with said cone and with said chamber, and means for effecting orbital movement of said screen member in said plane with respect to said casing and said cone to subject stock between said annular spaces to centrifugal action.

12. Screening apparatus of the character described comprising a main casing forming a generally conical chamber having an outlet at the lower end thereof, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with side walls of said chamber to leave an annular space therebetween for receiving r-screened stock through said screen member, a plurality of angularly spaced partition members arranged within said annular space to form therein a plurality of compartments adapted to be filled with the screened stock, a discharge trough positioned to receive material discharged over the upper rim of said screen member, an open-ended cone carried by said casingin telescoping spaced relation with said screen member to form therewith a second annular space, said supporting means for said screen member being constructed to position said screen member in substantially concentric relation with said cone and said chamber when said screen member is at rest, and means for effecting orbital movement of said screen member in said horizontal plane with respect to said casing and said cone.

13. Screening apparatus of the character described comprising a main casing forming a generally conical chamber having an outlet at the lower end thereof, a generally conical inverted perforate screen member adapted to receive stock for screening in the interior thereof, means supporting said screen member for movement with respect to said casing limited to a substantially l1 horisontal plane and with the lower end thereof extending into said chamber in spaced relation with side walls of said chamber to leave an annular space therebetween for receiving screened stock through said screen member, an openended cone carried by said casing in telescoping spaced relation with said screen member to form therewith a second annular space, said supporting means for said screen member including resilient means normally positioning said screen member in concentric relation with said cone and with said chamber, a plurality of arms secured to said screen member and extending inwardly thereof to form a centrally disposed hub, an cecentric weight mounted in said hub for rotation about the vertical axis of said screen, and drive means for rotating said weight to eifect orbital movement of said screen member with respect to said casing and said cone.

14. Screening apparatus of the character deporting said screen member for movement with respect to said casing limited to a substantially horizontal plane and with the lower end thereof extending into said chamber in spaced relation with side walls of said chamber to leave an annu- 13 iar space therebetween for receiving screened stock through said screen member, a plurality of angularly spaced partition members arranged within said annular space to form therein a plurality of compartments adapted to be filled with the screened stock, a discharge trough positioned to receive material discharged over the upper rim of said screen member, an open-ended cone carried by said casing in telescoping spaced relation with said screen member to form therewith a second annular space, said supporting means for said screen member being constructed to position said screen member in concentric relation with said cone at said chamber when said screen member is at rest, an eccentric weight carried by said screen member for rotation about the vertical axis thereof, anddrive means for rotating said weight to effect orbital movement of said screen member with respect to said casing and said cone.

BERNARD J. KOZIOL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 66,258 Sellers July 2, 1867 1,816,132 Strindlund July 28, 1931- 2,464,581 Jonsson Mar. 15, 1949 

